The striker has been linked with a move to China, but the former Blues midfielder feels that he needs to do more to reward the Premier League club
Former Chelsea midfielder Michael Ballack believes that Diego Costa needs to show more loyalty to the Blues.
Costa has been linked with a move to the Chinese Super League, with Tianjan Quanjian reportedly willing to pay the striker £400,000 a week.
The Spain international moved to Stamford Bridge in 2014, and has scored 47 Premier League goals in 74 appearances to date.
Ballack believes that Costa should repay the faith shown in him by Chelsea, and needs to ignore talk of a move to China.